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Several perturbation theory methods for accurate calculations on complex systems
Author(s) -
Barr Tery L.
Publication year - 2009
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560050726
Subject(s) - perturbation theory (quantum mechanics) , møller–plesset perturbation theory , brillouin zone , physics , perturbation (astronomy) , quantum mechanics , statistical physics
Several flexible methods based on perturbation theory are proposed for calculations on complex ( > 10 electrons) atomic and molecular systems. An iterative form of Feenberg perturbation theory is derived and its advantages are discussed. Calculations on Be using first‐order Feenberg theory are shown to be superior to those by Brillouin–Wigner and Rayleigh–Schrödinger schemes. It is suggested that by truncating the reaction operator t , a Brueckner–Bethe–Goldstone ( BBG ) type procedure can be developed which is applicable to atomic and molecular systems. Comparisons are made between the Feenberg, BBG , Kelly, and MC–SCF methods. The configuration–interaction perturbation scheme is put into many‐body form and suggested as an excellent composite approach for calculations on complex systems.